Time Enough for Love is a science fiction novel by Robert A. Heinlein published in 1973.

The book focuses on the adventures and musings of Lazarus Long, the universe's oldest living person, who has grown weary and has decided that life is no longer worth living. It takes the form of several novellas tied together in the form of Lazarus's retrospective narrative.

The Tale of an Adopted Daughter is a lengthy, western-style story about his days as a pioneer, which is rather un-SF fare for a book proclaimed as a SF classic. On the other hand, the pioneering does take place on another planet, and several genetically engineered animals — notably some talking, fertile mules — accompany Lazarus on his venture.

The Tale of the Man Who Was Too Lazy to Fail concerns a US naval cadet who manages to move up the ranks while avoiding any semblance of real work by applying himself wholeheartedly to the principle of "constructive laziness". Another story is the high-tech colonization of a planet in the "modern" way. There is a bit of time travel, and incest, at the end of the book.

There are two "Intermission" sections, each some six or eight pages long, taking the form of lists of provocative phrases and aphorisms, possibly based on the author's views on Life, the Universe, and Everything. Some of these have become quite popular and can be found (amongst other places) in internet signatures to this day.

This book is an outgrowth of the earlier Methuselah's Children and is connected to The Number of the Beast also by Robert A. Heinlein, The Cat Who Walks Through Walls, and several other Heinlein novels.

Finally, most of the events are told in first person from the point of view of the protagonist, Lazarus Long. Many are retold, also first person, from the point of view of his mother, Maureen Johnson Long, in To Sail Beyond the Sunset, the last novel Heinlein wrote and published before he died in 1988. This was, and still is, an uncommon approach to storytelling, and may be unique in fiction writing.

Editions

• 1973, Ace, hardcover, ISBN 0739419447
• June 1, 1973, Putnam Pub Group, hardcover, 605 pages, ISBN 0399111514
• 1974, Berkley Medallion Books, paperback, ISBN 0425024938
• December 1976, Berkley Publishing Group, paperback, ISBN 0425034712
• October 1978, Berkley Publishing Group, paperback, ISBN 0425043738
• March 1980, Berkley Publishing Group, paperback, ISBN 0425046842
• December 15, 1981, Berkley, paperback, ISBN 042505490X
• December 1982, Berkley Publishing Group, paperback, ISBN 0425061264
• November 1983, Berkley Publishing Group, paperback, ISBN 0425070506
• September 1984, Berkley Publishing Group, paperback, ISBN 0425079902
• November 1986, Berkley Publishing Group, paperback, ISBN 0425102246
• November 1994, Ace Books, ISBN 9994863959
• November 1, 1994, Ace Books, paperback reissue edition, 589 pages, ISBN 0441810764
• January 1, 2000, Blackstone Audiobooks, cassette audiobook, ISBN 0786118768
• January 1, 2000, Blackstone Audiobooks, cassette audiobook, ISBN 0786118946
• December 1, 2004, Blackstone Audiobooks, ISBN 0786189614